Together with the recent rapid growth of computer science, various contents are digitalized according to the improvement on the efficiency of the high-technology apparatus including A/D or D/A conversion device such as printer, scanner, digital camera, etc. Also, as the process of generating securities, etc. is digitalized, the technique forging or altering such is being developed day by day.
In this regard, the forged securities, etc. refer to securities, etc. that are newly made one similarly or identically with self-genuine copy (original copy) by a person who has no right to issue. Such forged securities, etc. are directly printed by using scanner or printer, or photocopied by using a color photocopier.
Further, the altered securities, etc. mean securities, etc. with their appearance changed wherein the change is made to the contents of the genuine copy of the securities, etc. For example, such alteration includes changing the face value amount from the low amount to a higher amount, or increasing the value of security by changing the issue date or interest payment date or changing specific particulars such as the name of the certificate, etc.
In accordance with the growth of forgery or alteration technique, the forged/altered securities, etc. have become very precise rendering the determination by naked eye to be ever more difficult. Specially, when the forged/altered security is circulated, the entire finance market including the security market will become chaotic, and furthermore, a national economic dislocation may arise. In order to prevent such chaos, various preventive measures such as below are established and managed.
1. Method Using Special Paper
A method using special paper includes use of watermark paper, pre-printed pattern, OMR sheet or chemical watermark, etc.
Watermark paper is manufactured by gluing two sheets of paper into one. When processing pulp to make paper, a method for revealing an appearance of pattern at light exposure by inserting pattern of a desirable shape using wire into the laminated paper (paper made by gluing two sheets of paper) is used widely for a primitive prevention of forgery.
There is also a method using security thread invisible except for wire or visible hidden line. The security thread includes several types such as insertion of consecutive characters, luminescence at the exposure of ultraviolet light, and appearance of particular figure or characters at the rise of temperature when rubbed by hands, etc.
The pre-printed pattern is technically difficult and rare, which leaves very little room for time or space for its use. Thus, when making securities usually small in numbers such as gift certificate, OMR paper is widely used which has better strength than other paper and triggers rejection reaction against the color photocopier.
The chemical watermark employs chemicals which actually have similar features as the watermark paper. The chemical watermark treated with chemicals is far more cheap and convenient to use than the watermark paper, and an effect similar to watermark paper can be obtained in its functional aspect. Thus, the chemical watermark is valuably used.
2. Design Method
The design method includes a hologram application method, a method using special pattern such as duplication prevention figure or concentric fine line, a method using micro-printing and a method of matching front/back copy, etc.
The hologram application method is a method designing and transcribing a desirable shape into the film, and heating the transcribed film for stamping on the paper. It is possible to stamp any desirable figure in the films such as various color of gold film, silver film, blue film, green film, black film, rainbow-color film and hologram film, etc. in similar cases. During the photocopying process, the light cannot penetrate the film, so the stamped portion is photocopied in black. Thus, a form different from the original is obtained so that forgery including duplication is prevented.
A method using special pattern such as duplication prevention figure or concentric fine line is very useful in preventing a forgery case which uses scanner or photocopy machine. When scanning or photocopying, the light is flashed uniformly from one end to the other end and the dark portion of the refractive wavelength wherein patterns are formed is folded. Such folded form is photocopied as it has shaped, and a distinctive difference rendered according to the space and color between the shapes is employed. The method using special pattern such as duplication prevention figure, etc. is recently emerged and a unique forgery prevention method.
A micro-printing(also referred to as ‘micro-lettering’) is a method involving the size of characters or figures to be at least certain level when the halftone dots are selected by color or white and black photocopier. Such method will result in a spoiled original form of characters or shapes when the characters or shapes are printed out at the lower level by a color photocopier.
A method of matching front/back copy concerns a preventive method against duplicate print of the front/back sides by a forger forging the design. When photocopying twice for forgery, matching accurately the print out of the front side with the print out of the back side is a very difficult task for an ordinary technique. By applying the method of matching front/back sides, it is possible to prevent forgery of forging twice with the front and back sides.
The above-mentioned design methods play a big role in preventing the forgery/alteration of the securities. Forgery/alteration by an ordinary user without special device is fundamentally impossible.
3. Method Using Special Ink
A method using special ink includes a conventionally used fluorescence method, a method using ink for convexo-concave print, a method using metal ink (gold powder, silver powder, etc.), and a method using thermographical discoloration ink, unchangeable ink and chemical reactive ink, etc.
The fluorescent method involves a fluorescent phenomenon occurring from a mixture of fluorescent material and ink at the exposure of ultraviolet light, which is not visible by naked eye, but distinguishable only by ultraviolet light. This method is the most universally used forgery prevention technique at present times. Since it is not distinguishable by print-outs, its forgery prevention effect is very excellent. Its original use is intended for examining whether there is crack after welding the joints of the highly precision machine such as ships or spaceships, etc., but now it is applied in printing. The effect thereof is very good when simultaneously using both as it is visible by naked eye and it involves fluorescent ink.
4. Special Print Method
A special print method involves an integral printing, rainbow printing, negative printing, bar code printing, OCR, and MICR numbering printing, etc.
The integral printing is not a printing process of the general PS plate or of baking the film on a flat plate, but of corroding stainless copper plate, printing in ultraviolet ink, and drying by passing through ultraviolet light. When the surface is examined, a jagged convexo-concave phenomenon appears on the paper surface. Similarly imitating, a similar effect may be obtained by completing the printing before making the copper plate, and making convexo-concave by compressing with platon or press.
The rainbow printing is a process of printing each of several portions of parts made of a film or a plate in different colors, respectively. Such process involves removing a vibration roller installed for the purpose of blending the ink well among the machinery rollers, blocking the spot where the ink is distributed according to different colors, and letting the ink poured down as it is in a straight line.
The negative printing is accomplished by number of lines representing the thickness of between halftone dots when all the printing is accomplished. The general printing uses 175 lpi (lines per inch), the gift certificate uses at least 200 lpi and the photograph uses 1200 lpi. The current printing has been improved to the extent of using 1200 lpi. When printing with the angles between halftone dots well blended to make a pattern shape and to print, it is difficult to distinguish by naked eyes, but when photocopied, only the twisted/spoiled halftone dots are photocopied so that a pattern completely different from the original is photocopied.
The bar code printing is a process printing the previously prepared inputted bar codes. The forgery becomes impossible since the forger cannot confirm what content has been inputted.
In OCR, MICR numbering printing, the numbering itself has been established by encryption which is a special numbering having its own checking system. OCR detects with light, and recognizes magnesium blended in MICRDMS ink as magnetic material. The forger on the outside does not know the established codes so the forgery is impossible. OCR is widely used in preventing the forgery and alteration of the stock certificate, and MICR is a numbering method used for preventing the forgery/alteration of checks.
The aforementioned methods to prevent the forgery/alteration such as the method using special paper, the design method, the method using special ink, the method using special print, etc. are based on the safety of the forgery/alteration prevention methods relying on the specialty of ink or paper, etc. necessary for making all securities, and the weakness of the peripheral units such as a printer, a photocopier, etc. themselves.
Accordingly, the manufacturing cost is relatively expensive, the detection of forgery/alteration is different from each other in its detection devices or methods according to the difference in each respective method of use and manufacturing method. Particularly, an assistance from a certain institution when making securities is always necessary. It is very general that a certain institution monopolizes issuance of securities, otherwise a certain public trust attested by a certain institution is depended upon. Thus, in order to make securities applicable of forgery/alteration prevention techniques, involvement of several numbers of certain institutions is necessary.
Furthermore, a method for determining the forgery/alteration and an apparatus thereof are not universally accepted. Thus, for ordinary users to determine forgery/alteration, a considerable knowledge is required and the users should be in possession of a discerning ability corresponding thereto.
Also, recently the securities, etc. are all manufactured by digital file. However, the digital file made prior to the issuance in the paper form, in its features, has a problem which makes the authentication of the original copy impossible due to easy forgery/alteration, and unlimited duplication.
Accordingly, it is impossible to issue securities, etc. only by digital file itself.